A Upper Animas Mining District
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United States Environmental Protection Agency • Regions • May 2015
Red and Bonita Mine
Introduction
The EPASuperfund Program is conducting a time-critical
removal action at the Red and Bonita Mine site during the
summer 2015. The action involves installing an
engineered, reinforced bulkhead {i.e. massive plug) to
control the discharge of contaminated water coming out
of the mine adit {i.e. tunnel) and flowing into Cement
Creek, a tributary of the Animas River.
Along with this work, EPA also plans to remove the
blockage and reconstruct the portal at the Gold King Mine
in order to best observe possible changes in discharge
caused by the installation of Red and Bonita Mine
bulkhead. The Gold King Mine is the closest mine to the
Red and Bonita Mine and is located higher on the
mountain. Entry into the Gold King Mine workings will
depend on the conditions encountered following portal
construction.
Need
EPA is undertaking this work because of the impact heavy
metals in acid mine drainage from the Red and Bonita
Mine adit have on water quality in the Animas River.
Water quality standards are not achieved in the Animas
River near Silverton.
The discharge from the Red and Bonita Mine represents a
significant contribution of heavy metals, including zinc, to
the Animas River.
Sampling results in 2012 and related USGS modeling show
the discharge of acid mine drainage from the Red and
Bonita Mine accounts for an estimated 18 percent of the
zinc load at station A72, a location on the Animas River
one mile below Silverton.
Impacts to aquatic life are demonstrated by fish
population surveys conducted by Colorado Parks and
Wildlife, which found no fish in the Animas River below
Cement Creek for approximately two miles and observed
precipitous declines in fish populations as far as 20 miles
downstream since 2005.
Bulkhead Construction
Goal
The goal of this removal action is to prevent or reduce
continued releases of heavy metals into the environment
from the Red and Bonita Mine. The bulkhead, which will
include a valve, will provide a hydraulic control to prevent
and/or manage the ongoing discharge of approximately
300 gallons per minute of acid mine drainage from the
Red and Bonita Mine to Cement Creek.
By retaining the water in the Red and Bonita Mine
workings, the water-filled portions of the workings will
gradually be denied the oxygen that contributes to acid
production and leaching metals.
Water quality monitoring will be performed before and
after the bulkhead is constructed and the valve closed.
Conditions will be monitored over the course of the year,
including monitoring nearby mines for changes in flow
and water quality.
The bulkhead will be constructed with piping and a relief
valve to allow the option of restoring free flowing
conditions. The water level behind the bulkhead can be
reduced, if this is deemed necessary, to address adverse
impacts. If future remedies require the need to move
water to another location, the piping will be in place at
the bulkhead to allow for controlled management of the
flow.
Anticipated Results
It is anticipated that zinc concentrations in the Animas
River below Silverton will be reduced soon after the
bulkhead valve is closed. Sampling will be performed to
assess the changes. Other changes may include an
increase in flow from nearby adits, which EPA will also
monitor.

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The Red and Boriita Mine site consists of
approximately 1.25 acres of waste rock and
suspected tailings material and includes an
estimated 3,500 feet of underground
workings.
The Red and Bonita Mine is located within the
Cement Creek watershed, a component of the
Upper Animas River Watershed, in
unincorporated San Juan County, Colorado.
The portal is located approximately seven
miles north of the Town of Silverton, at 10,893
feet above mean sea level.
Planned Activities
The EPA plans to begin work at the Red and
Bonita Mine in July 2015.
Installation of the bulkhead includes the
following elements:
1)	Establishing temporary water treatment
and settling pond(s);
2)	Removing the precipitated solids (i.e.
sludge) from approximately 300 feet of the
mine adit;
3)	Constructing an onsite repository for the
solids removed from the mine;
4)	Preparing the section of the adit for the
bulkhead;
5)	Constructing the concrete bulkhead with
piping and valves for future management
flexibility.
FOR MORE INFORMATION , PLEASE CONTACT THE FOLLOWING:
Steve Way
On-Scene Coordinator
303-312-6723
way.steven@epa.gov
U.S. Environmental Protection Agency, 1595 Wynkoop St., Denver, CO 80202
Liz Fagen
Remedial Project Manager
303-312-6095
fagen.liz@epa.gov
Paula Schmittdiel
Remedial Project Manager
303-312-6861
schmittdiel.paula@epa.gov
Cynthia Peterson
Community Involvement Coordinator
303-312-6879
peterson.cynthia@epa.gov
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Red and Bonita Adit
Background
The watersheds within the volcanic terrain of the San
Juan Mountains were the focus of both large- and small-
scale mining operations between 1871 and 1991.
Historic mapping of the Red and Bonita Mine indicates
that mining operations began prior to 1899
and lasted for only a short period of time.
Bulkhead construction is targeted for completion on or
before Sept. 30, 2015. Valve closure wili occur sometime
shortly after completion.
Figure 1: Red and Bonita Location Map
To Silverton
May 2015
Page 2

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